Comtech EF Data DMD1050 User Manual
Page 57
DMD1050 Satellite Modem Board
Theory of Operation
MN-DMD1050
3–31
Revision 9
3.17.3 Overhead Rate Comparison
The SCC Overhead Ratio varies depending on the User Data Rate, the In-Band Rate, and the
Control Ratio. This gives SCC the advantage of lower overhead rates when compared to IBS,
which has a fixed overhead ratio of 16/15 or 1.067. The following table gives some examples of
SCC overhead rates for different user data and control ratios.
User Data Rate In-Band Rate Control Ratio Aggregate Data Rate Overhead Ratio
512,000
19,200
1/7
533,974
1.043
1,024,000
19,200
1/7
1,045,974
1.021
2,048,000
19,200
1/7
2,069,951
1.011
3,072,000
19,200
1/7
3,093,943
1.007
4,096,000
19,200
1/7
4,117,951
1.005
6,312,000
19,200
1/7
6,337,248
1.004
6,312,000
19,200
1/3
6,337,606
1.004
6,312,000
19,200
1/1
6,350,418
1.006